The Job Openings and Labor Turnovers Survey (JOLTS) may not get as much attention as the monthly jobs report, but Yellen has cited JOLTS in the past as one of her favorite labor market indicators.

So market-watchers would be wise to keep an eye on JOLTS, which is due out at 10:00 a.m. ET today. It may not be very market-moving, but it's the kind of indicator that could spur the Yellen Fed to alter monetary policy, especially as unemployment nears Fed targets in the coming years.

Here's where we are in four key metrics ahead of today's report.

Job openings are trending upward.

Hires are still way below pre-recession levels.

Layoffs are down, but as we've written before, it could be a sign of labor hoarding. The idea here is that firms hold on to the labor they have in times of trouble and try to maximize their productivity. Until hires break through, the fact that layoffs are low doesn't really tell us all that much.

The quit rate is still fairly low. The higher the quit rate, the better, since people generally leave their jobs when they are more confident in the job market.